High-Frequency PCB

– Circuit Board Fabrication and PCB Assembly Turnkey Services – WellPCB
  • High frequency PCBs are ideal for applications that involve special signal transmissions between devices
  • These PCBs also involve the use of special materials to achieve a high frequency
  • High frequency PCBs produce high frequency signals that have tighter impedance when compared to conventional PCBs

What is High Frequency PCB?

Are you dealing with wireless networks or applications that include particular signal transmission amid objects? Then consider getting a high-frequency PCB.

These PCBs come in a frequency range of 500MHz to 2GHz. You can use them in different applications like high-speed design applications, microwaves, mobiles, etc.

There’s a lot of signal sensitivity that comes with this type of PCB. Thus, it has high-frequency laminates that help to sustain the thermal heat transfer of the application.

Also, the type of high-frequency board you choose will determine the overall performance of your signal. If there’s any change in the material’s dielectric constant, it will affect your board’s impedance.

Key Features of High
Frequency PCB

  • Small and stable. Besides,no delay in signal transmission.

  • Ideal for signal transmission. And reduce signal wastage effectively.

  • No copper foil separation with temperature changes.

  • HF boards with low water absorptivity.

  • Impressive properties like impact endurance, heat resistance, peel off resistance, and chemical resistance. Plus,High peel-off resistance improves the PCB's signal quality.

  • Adequate spacing for boards. And It also has smaller diameter vias and invariably low conductance.

The Required Materials for High
Frequency Circuit Board

High-frequency circuit boards have specific demands on the materials they use. So, a great example is its improved permittivity.

We also have other needs similar to construction with reduced tolerance in DK and insulation thickness. It also includes a reduced attenuation for competent signal transmission.

We choose an adequate layer buildup for most of our applications and use FR4 material (considering that it’s sufficient to use). Also, we use enhanced dielectric properties to process high-frequency materials.

And it’s because it’s frequency independent, has a low DK, and low loss factor. Other properties that we include are an extremely low hydrophilic rate, high glass transition temperature, and remarkable thermal durability.

Some of the materials we use are Taconic TLX, Rogers, ISOLA IS620 E-fiber glass, etc.

Here’s a table that explains each of the material’s properties:

Materials for HF circuit boardsTg (℃)CTE-z (PPM/℃)Peel Strength(N/mm)Td Value (℃)DK Loss TangentThermal Conductivity (W/m*K)Surface Resistivity(M)Electric Strength (KV/mm)Ԑr (@10GHz
ARLON 85N250551.23870.01000.201.6 x 10^9734.2
Rogers 4350B280320.93900.00370.695.7 x 10^9313.5
Rogers RO3010161.65000.00220.951 x 10^510
ISOLA IS620220541.20.00802.8 x 10^64.5
Rogers RO3006241.25000.00200.791 x 10^56.2
Rogers RO3003251.25000.00130.501 x 10^53.0
Rogers RO30011602.10.00300.221 x 10^9982.3
Taconic TLC702.10.241 x 10^73.2
Taconic TLX1352.10.00190.191 x 10^72.5
Antennas and power
Cell phones
RF identification tags
Medical appliances
Automotive radar systems
Millimeter-wave applications
Global positioning satellite
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Applications of High
Frequency PCB

 

Antennas and power amplifiers
Cell phones
RF identification tags
Medical appliances
Automotive radar systems
Millimeter-wave applications
Global positioning satellite antennas

Why You Should Consider Getting
High Frequency PCB

–With a high-frequency PCB, you can get a lot of benefits like:

Reduced Moisture Rate

  • When it comes to moisture, a small amount can distort a high-frequency board's electrical performance. Interestingly, materials like the PTFE have a moisture rating as low as 2% compared to the traditional FR-4. FR-4 has a high rating of about 50%. So, a decreased moisture rate translates to a remarkable electrical performance.

Excellent Thermal Management

  • Most times, high frequency PCBs tend to produce a lot of heat during operation. So, with materials like polyimides, you can rest assured that you'll get robust thermal properties. Plus, you can use them in harsh environments as well.

It Has a Controlled Impedance

  • The boards contain materials that hold their Dk tolerance at +/-2% or more. That means it's quite useful for circuits that require tight, controlled impedance..

Excellent Signal Performance Across the Board

  • Thanks to its PTFE materials, there's a low dissipation factor. And it also means that it decreases signal loss.

It Comes with Dimensional Stability

  • High-frequency PCBs have thermoset hydrocarbon materials. These materials promote mechanical stability.

The Guidelines for High Frequency
PCB Design & Layout

–The sure ways to achieve a reasonable layout plan and suitable wiring for a high-frequency PCB include:

1. Fewer vias in your connection

Ensure that you have fewer vias in your connection because when you use a via, it produces a distribution capacitance of 5 x 10-13F. So, reducing the via leads to a drastic increase in speed. Plus, it decreases the chance of having data errors.

2.Make a high-frequency lead longer

 In this step, the science is that the signal line’s routing length is directly proportional to the radiation intensity. With that in mind, it means that when the high-frequency lead is longer, you’ll find it easy to couple its parts.

3.Reduce the bend

Reduce the bend that exists between the pins on the high-frequency board. Most times, it’s ideal to use a full straight line when you’re wiring the HF boards. If you must have a break over, use an arc break or a broken line at 45 degrees. Consequently, you’ll enhance the copper foil’s bonding strength in low-frequency circuits. But this step isn’t necessary for high-frequency circuits. And it’s because it decreases the outer emissions.

4.Reduce the crosstalk

Don’t take the crosstalk from the signal line for granted. The crosstalk occurs between signal lines that lack a direct connection. So, it’s best to reduce the crosstalk that occurs in high-frequency signals.

5. Try not to have loops

Try not to have loops when you’re wiring the HF board. If they occur, make them extremely small.

The Few Bottlenecks with
Manufacturing HF Boards

–Some of the slight challenges you may encounter with HF boards include:

Copper Foil Finish for High Frequencies

When there is an increase in frequency, the signal flows through the track. And the track produces current. Then, the current pushes current density to the outer surface instead of the center of the track. So, during production, you may experience increased roughness of the copper surface. As a result, there will be loads of signal losses at high frequencies.

Solder Mask at High Frequencies

Soldermask has a high dissipation factor. So, when you apply it on traces with high frequency, it boosts the circuit’s dielectric loss.

How to Produce Controlled
Impedance Transmission Lines?

–The aim of creating controlled impedance is to avoid signal loss. And there are two simple ways you can achieve that goal:

Microstrip Method

This method has to do with having the trace on the top layer. And the trace usually has a ground plane under it.

The calculation involved in this method is quite complicated. Plus, it relies on different factors like height above the plane, relative permittivity, width of the trace, etc. So, your best option is to ensure that your ground plane is quite close to the top layer.

Stripline Method

The stripline method is similar to the microstrip, and the only difference is that the stripline has an additional group plane. And the group plane is on top of the trace. While using this method, ensure that you put the trace between the two planes. This method is a better option. And the reason is that within the two planes, there’s EMI radiation.

WELLPCB- Your High-Frequency
PCB Manufacturer

WellPCB has a wealth of experience in the field of PCB production. So, you can trust that you’ll get remarkable performing high-frequency PCB fabrication services. And our board usually ranges from 500MHz to 2GHz.

Here’s a table to give you an idea:

HF MaterialsDk
RO30033.00±[email protected] GHz
RO4350B3.48±[email protected] GHz
RT58802.20±[email protected] GHz
RO4003C3.38±@10 GHz
RO301010.2±[email protected] GHz
What is our capacity in general?
  • Properties
    Capacity
  • Thickness of board:
    0.4 – 5.0 mm
  • PP:
    Domestic- (6700), Rogers 4450F, etc.
  • Silkscreen sides:
    It depends on the file.
  • Number of layers:
    2 – 32 layers
  • Alternative methods:
    Countersink holes, Gold fingers, Peelable solder, mask Carbon oil
  • Silkscreen color:
    Black, yellow, white
  • Surface finish:
    Immersion tin – RoHS, ENIG – RoHS, Organic solderability preservatives – RoHS, Immersion silver – RoHS
  • Build time:
    It depends on the project (2 days to 5 weeks)
  • Minimum tracing:
    3mil/3mil
  • Material:
    RO3010, RO4350B, RT5880, RO4003C, RO3003
  • Order quantity:
    1 – 10000+pcs
  • Solder mask color:
    Blue, red, yellow, green, white
  • Quality grade:
    Standard IPC 2
  • Board size:
    0.4-5.0 mm
  • Min drill hole diameter:
    6mil
  • Finished copper weight:
    0.5 – 2.0 0z
  • Min annular ring:
    4mil
  • Impedance tolerance:
    ±10%

FAQs

1. How to choose the board material of high frequency pcb/High-speed PCB Materials?

For the selection of materials, FR-4 material is the common laminate material. Other substrate materials, except for alumina substrates, like PPO and Teflon are also in use as frequency laminates. Furthermore, you also need to consider the material combinations,  dielectric material, carrier substrate of the PCB substrate.

2. How about the signal integrity issues in high-frequency signal transmission?

Signal integrity is to measure these signal distortions in the high-frequency regime. signal traces, the signal layer, and signal energy may affect the efficient signal transmission. For more about the high-speed signal, please contact our team.

3. What to consider in the High-speed PCB design/High-frequency designs?

First, consider circuit designs’ design rules such as PCB layout design, the design process in the electronics design. Besides, your high-frequency applications determine the circuit performance you need. Such as characteristic impedance, mechanical strength, thermal characteristics (thermal expansion), chemical resistance, loss tangent, heat dissipation. Then,  layer thickness, PCB Component (critical components) of the electronic device, digital circuitry,  conductive layers. Also,  antenna arrays, antenna efficiency, conductor losses are also important factors to consider.